When confronted with various spinal diseases, injuries, and conditions, it is often desirable for a spinal surgeon to perform an interbody fusion or the like, whereby adjacent vertebrae are fused together using a bone graft and/or an implantable device, or otherwise immobilize a portion of the spine of a patient, either temporarily or permanently. Typically, in the interbody fusion case, the adjacent vertebrae are immobilized while the bone graft is allowed to “take,” for example, using a conventional pedicle screw system, a plate system, or the like. Such a pedicle screw system consists of a plurality of pedicle screws that are anchored to adjacent levels of the spine and connected with stabilizing rods or the like. Such a plate system consists of a plate that is anchored to adjacent levels of the spine and, optionally, connected to the implantable device. Another potential option when treating various spinal diseases and injuries is to immobilize the associated facet joint(s) using one or more facet bolts or the like. In order to accomplish this, the superior and inferior facets to be joined must be aligned and securely held during drilling and bolt placement, for example. It is also sometimes desirable that they are compressed either before or during drilling and bolt placement.
Conventional pedicle screw systems consisting of a plurality of pedicle screws that are anchored to adjacent levels of the spine and connected with stabilizing rods or the like, typically utilize pedicle screws that are exclusively monoaxial or polyaxial. These monoaxial pedicle screws, which have a rod-receiving head that is fixed in orientation in relation to the threaded portion of the screw, disadvantageously must initially be placed in precise alignment with the pedicle or other bony structure in which they are disposed and provide little subsequent flexibility. The alignment of the engaged rod is set by the initial placement and orientation of the screw. These polyaxial pedicle screws, which have a rod-receiving head that is movable in orientation in relation to the threaded portion of the screw, disadvantageously must be placed in a desired alignment simultaneous with rod placement and often provide too much flexibility. The alignment of the engaged rod is not set until the rod is placed and secured. Both types of pedicle screws typically utilize one or more set screws to provide pressure on the rod, which in turn provides pressure on the head of the pedicle screw. What is often needed in the art is a pedicle screw system, or other surgical screw system, that allows the threaded portion of the screw to be secured in a bony structure, the angle and orientation of the head to be subsequently selected and secured, and then the placement and securement of the stabilization structure performed. In other words, what is often needed is a polyaxial-to-monoaxial screw system.